1. Field of the Invention
The present invention relates to an image processing apparatus and, more particularly, to an image processing apparatus having display means to monitor and display information from a data input section.
2. Description of the Prior Art
A copying machine (or copier) is an example of an apparatus used to optically read an original and perform image processing. In typical copiers, a transparent original placed on an original plate is lit from under the original plate and the reflected light corresponding to densities of the original are focused by an optical system using a lens and the like, and an image of the original is formed on a light sensitive drum.
Recently, with regard to image processing apparatuses, an apparatus has been proposed which can hard-copy an image displayed on a display unit or the like, for example, an output from a computer or the like as well as an ordinary original in the manner similar to ordinary originals.
In the case of a display panel copy, a reflection type liquid crystal panel arranged with high density is disposed on an original presser plate of a copier and when this original presser plate (or original plate cover) is open, a display (e.g., liquid crystal) panel is made operative as a display medium for information. This display panel is constituted such that it is connected to a FAX system or an office computer, or it is connected as an output terminal of a word processor and the like from an external section in the company, in this way, it is used as one form for transmission of information, and that, if necessary, the cover is put down as in the manner to make an ordinary copy and the display is lit and scanned in order to retain that information as a hard copy.
FIG. 1 illustrates a perspective view of an image processing apparatus whereby a copier and a reflection type liquid crystal display of which an original cover of the copier is constituted by a reflection type liquid crystal display unit are combined. A reference numeral 1 denotes a copier of the electrophotographic system and 2 indicates an original cover which is constituted such that it has a reflection type liquid crystal display (or LCD) 3 formed so that it can cover an original plate glass 4. The reflection type LCD 3 is connected to a personal computer 5 equipped with a keyboard through a cable 6. The original cover 2 has such a structure as to protect the display screen 3.
With such an arrangement, processing information is first displayed on the display screen by use of the display screen 3 as an output of a console of the computer 5 and after confirming the content displayed, by putting down the reflection type LCD 3 on the cover and by setting a copy key on the copier main part 1 or on the keyboard to start the copying operation, a hard copy of the display content can be easily obtained. Particularly, when the computer 5 is used as a word processor, after correcting and confirming a document outputted on the display screen 3, the document is obtained as a hard copy as it is, so that it is extremely effective regarding its operability. On one hand, in the system which adopts a local area network and can perform the transfer and the like of information by combining a plurality of computers 5, image information is transferred among, offices and the like and the image information is transferred on the display screen 3 and is output thereon. After confirming the content displayed, only the necessary information can be easily left as a hard copy, so that it is very useful. Moreover, if the area on the screen is ordinarily all blank, the copier 1 can be obviously used as a general copying machine for documents; therefore, this system is valuable as an apparatus of which an equipment which is generally used for office works was constituted as a compact apparatus.
FIG. 2 illustrates an internal constitutional diagram of the copier 1. The closable original presser plate 2 is arranged over the original placing section 4 consisting of transparent member and this presser plate 2 serves to press and closely retain an original placed on the upper surface of the original placing section 4; this is similar to that in this kind of well known copier. The display panel 3 consisting of reflection type liquid crystal cells is arranged on the inner surface of the original presser plate 2 in the manner such that it is closely retained on the original placing section when it is closed. Output information from a computer or the like (not shown) is displayed as an image.
Therefore, when the output image is displayed on the LCD panel 3, by performing the copying work similarly to the case where an original which is copied is placed on the corresponding location, the output image is lit by an exposure light source 50 provided in the copier. Thus, the reflection light responsive to the output image is formed on a light sensitive material 56 through mirrors 51 and 52, optical system 53, and mirrors 54 and 55. Thereafter, a hard copy of the image displayed on the LCD panel will be theoretically obtained in the manner similar to the that performed in well known copiers.
However, practically speaking, if the image on the LCD panel 3 is merely used as it is in place of using an ordinary document or the like as an original, a clear copy cannot be derived because of the lack of proper illumination.
On the contrary, even if the illumination is increased, the whole copy will be made light and will cause drawbacks such that it is difficult to obtain good gradient and that the electric power consumption also increases.
The above-mentioned LCD panel 3 is, for instance, of the reflection type LCD cells of the publicly known twisted nematic type and its cross sectional structure is shown in FIG. 3-1. Namely, transparent electrodes E and E are arranged respectively on the inner surfaces of two sheets of transparent substrates G and disposed in parallel. The space between the transparent substrates held through spacers S is filled with a liquid crystal L. Numerals 26 and 27 denote deflecting plates and 28 is a reflecting plate. As is well known, the action of such a LCD panel is such that the light projected from the direction indicated by an arrow a in FIG. 3-1 is deflected by the deflecting plate 26 and progresses, and at this time it is determined whether or not the light emission is performed at the portion of the liquid crystal L in dependence upon whether or not an electric field is applied to the electrodes E, then the light further progresses and it is discriminated by the deflecting plate 27 whether or not the light is allowed to pass therethrough. The light passed through the deflection plate 27 (namely, the deflected light) is reflected by the reflecting plate 28 and it is again determined whether or not it is allowed to pass through the deflecting plate 27, liquid crystal L and deflecting plate 26 in the similar manner as mentioned above in dependence upon the presence and absence of the electric field. Therefore, when it is assumed that one pixel is constituted by a pair of such electrodes E and by arranging a number of such pairs and by appropriately determining whether or not the electric field is applied to each pair, a picture image can be formed.
In case of forming an image using the LCD panel in this way, there are many elements to attenuate the light until the projection light passes through the LCD panel and is again radiated to the outside, so that an amount of reflected light is less than an amount of projected light. Therefore, this method is disadvantageous to perform copying by the above-mentioned method shown in FIG. 2.
Further, in the copying method shown in FIG. 2, the light at the portion having a large amount of light in the mirror reflecting direction (refer to FIG. 3-2 which illustrates an explanatory diagram of the mirror reflection) is not used, but the light at the portion of the diffused reflection is ordinarily used as the light which is finally projected onto a light sensitive material among the lights which were projected from the light source 50 onto the original surface. This is because the use of the reflected light in the mirror reflecting direction causes the contrast of the original to deteriorate due to influence by the reflected light from the surface of the glass plate of the original placing section 4. In FIG. 3-2, a numeral 3a denotes a reflecting plate and 57 is an optical system and the light from the light source 50 is reflected by the reflecting plate 3a. This reflected light includes a larger amount of mirror reflected components (in the direction of b) and a less amount of light which reaches the optical system 57.
This fact is fundamentally similar to the case of using the reflection type LCD plate as an original as mentioned before. It is in fact impossible to use such a plate as an original for a copier when the reflecting surface of the reflecting plate 28 is a complete mirror reflecting surface. Also, even if the reflecting surface is an irregularly reflecting surface, a sufficient amount of light cannot be obtained since the liquid crystal cells themselves have a large attenuation property as mentioned before, so that it is difficult to derive a clear picture image.
On the other hand, in the composite image processing apparatus shown in FIG. 1, it is impossible to simultaneously execute in parallel the hard copy process of the image which was monitor-displayed on the display means and the hard copy process of another image of an original, for instance, written on a paper for an original. For example, when an LCD device is used as the display means, the location of the image displayed on the LCD panel which was led onto the exposing location of the original (i.e., on the original plate glass) differs from the location of the image of the original placed on the original plate glass. Namely, as shown in FIG. 4, in case of the LCD panel, the liquid crystal L serving as the image forming section is held in the space which is constituted by the spacers S, supporting glass plates G and transparent electrodes E. On the other hand, since the original is directly placed on the original plate glass and is pressed by the supporting glass plate G, the location (or level) of the image differs by an amount corresponding to at least the thickness of this supporting glass plate G. It is necessary to compensate this difference in level between both images by varying the image forming process such as, for example, by adjusting a focal point by changing the location of the exposing lens, or the like. Thus, this certainly makes the apparatus complicated. In addition, since it takes a constant period of time to perform the focal point adjusting operation, it is impossible to simultaneously copy both of the image displayed on the LCD means and the image of the original and thereby to synthesize a clear hard copy.
It is also impossible to simultaneously write both images at an arbitrary portion on the original. That is, there is a drawback such that the simultaneous writing portion by the screen of the original has to be preliminarily cut away or the original has to be made of transparent material such as an OHP (overhead projector) sheet or the like.
On the other hand, since the above-mentioned image processing apparatus is constituted on the premise that it can be operated as an ordinary copier, the original plate is arranged such that an original of an A3 size is laterally placed thereon in general when it is seen from the operator side in order to enable an original of up to an A3 size to be copied. Therefore, the information transmitted is displayed on the plate display having a format of which the A3 size is placed laterally. However, the formats of information generally differ depending upon the content of the information. For example, in the case where the A3 information is written laterally in the direction along the short side, there is a drawback such that even if it is displayed as it is, the operator cannot easily read it. In addition, in the display format whereby the information of the A3 size is reformed from the longitudinal direction to the lateral direction so that the information can be easily read, in the case where it is copied by putting down the display unit in this state, another drawback will be caused whereby there is inconvenience such that the A3 information cannot be reproduced on a sheet of A3 transfer material.
On the other hand, in the above-mentioned apparatus, the display 3 and personal computer 5 as illustrated in FIG. 1 are connected through the cable 6 and the signals are transmitted and received therebetween by this cable. The display 3 is opened and closed when the display image is checked and copied. Therefore, whenever it is opened and closed, this could make the mechanical burden too heavy for the cable 6 and connectors and the like, causing a problem of damage such as the breaking of signal lines in the cable and the like. As the number of signal lines in the cable increases, the risk of such a damage increases more and more.
Further, in such an apparatus, since the copying apparatus and display apparatus are mutually independently provided, to reset the display apparatus into the state in that the copy is possible after an image has been once displayed on the display apparatus, the original cover has to be once put down on the original plate. Thereafter, the copy is done by further setting the copy start button of the copier main body. Therefore, in the case where, e.g., the display screen (information) on the display apparatus is sequentially changed and information is checked and correcte and then copied, namely, in the case of repeating such operations, the above-mentioned copying operation has to be performed every time. Also, after closely pressing and sticking the display apparatus on the original plate glass, the copy start button is depressed to obtain a hard copy. Consequently, there is a drawback such that the operations are very troublesome and difficult.
Moreover, if the copy button is depressed after completion of the inputting operation to the display apparatus and the image processing operation is executed, the leading time until the image processing can be performed becomes vain. Conversely, if the image processing operation has been preliminarily enabled before the information is input to the display apparatus, there is a drawback such that it is undesirable from the viewpoint of power saving.
On one hand, in the above-mentioned apparatus, when the display means of the TN type is employed as the LCD panel, the deflecting plates are used to provide the visible information, so that an amount of reflected light forming an optical image largely attenuates as compared with an amount of light which is radiated onto the display surface. Therefore, although there is no problem in particular when the display information is directly observed with the naked eye, as an optical image which is applied to a conventionally well known light conductive layer, a drawback is caused whereby proper illumination is lacking and a clear hard copy with large contrast cannot be derived.
In addition, in case of a copier, the exposing light source is generally arranged such that it can obtain a copy of the image written on the material which is ordinarily the irregular reflecting surface. On the other hand, in case of the image formed in the liquid crystal cells, it is well known that a difference is caused in image contrast in dependence upon the location of the light source and the direction where the picture image is observed. Therefore, as mentioned before, by merely using a well known copier and placing the image of the liquid crystal cells on the original placing section, a good contrast image cannot be applied onto the light sensitive material in the copier.
The difference in contrast in the liquid crystal cells depending upon various directions will then be discussed. In FIGS. 5-1 and 5-3, a numeral 21 indicates a display surface of the liquid crystal cell and a point O is used as a contrast measuring point. A numeral 22 represents a plane which passes through the point O and is perpendicular to the plate 21. For this plane 22, FIG. 5-2 shows a curve on a graph whereby a contrast ratio is shown with respect to an angle .phi..sub.A in the case where a brightness measuring instrument 24 is rotated in the plane 22 around the point O as a rotational center from a point A to a point A'. FIG. 5-3 shows the case where the contrast ratio is measured in the similar manner as mentioned above along the plane which passes through the point O and includes a straight line B-B' which perpendicularly crosses a straight line A-A'. FIG. 5-4 shows a value of the contrast ratio regarding an angle .phi..sub.B.
In FIGS. 5-2 and 5-4, the solid lines indicate the case of the TN type liquid crystal, while the broken line represents the case of the GH type liquid crystal, respectively. It can be seen soon from these graphs that the maximum contrast (visual dependability) is obtained in the direction perpendicular to the liquid crystal surface when the image is seen from the direction indicated in FIG. 5-3, while the maximum contrast (visual dependability) is derived at the location which is about 40.degree. apart from the location perpendicular to the display surface in the direction indicated in FIG. 5-1. This is remarkable in the TN type liquid crystal, but the GH type liquid crystal also has a similar tendency.
The above description will now be summarized as follows. In this way, in case of the LCD apparatus, the light and shade are caused in its output image depending upon the directions where it is seen. Thus, when the liquid crystal display surface is attached onto the original presser plate of the copier mentioned above or the like, there is a problem of occurrence of the case where even if an image is displayed on the display surface, it is difficult to see the image.